1. Field of the Invention
The present invention relates to electrical interconnectors. More particularly, the present invention relates to an electrical interconnector which acts as an interposer between opposing arrays of conductors and may be used for making connection for contact testing of single chips or a full wafer of chips.
2. Background and Related Art
Various techniques exist in the prior art for making the connection of electronic devices to one another at electrical contacts, be the contacts wire bond pads, solder ball contacts or similar type connection points. One reason for making these connections is for device test purposes. Device testing apparatus typically takes the form of an array of test probes which align with the array of electrical contact points on the device to be tested. These probe arrangements, however, have limitations, such as, physical limitation because of the size and spacing of their probes as compared to the size and spacing of contact points in high density devices. Thus, with the increasing density of contacts on chips, for example, it becomes more and more difficult to fabricate probe arrays with probe densities adequate to make proper electrical connection to a chip, wafer or substrate. Another limitation to known probe arrangements resides in the limitations on their clock speed. Typically, the clock speed of such arrangements is limited to no more than around 400 MHz.
In accordance with the teachings of the present invention, a high density Z-axis connector or interposer is provided which allows for making good conformal contact to an array of dense electrical contact points on a chip, wafer or similar electrical device. The connector or interposer may be used between opposing sets or arrays of contacts, as between, for example, the array of contacts on a chip or wafer and the corresponding opposing array of contacts on the underlying substrate. Such an arrangement may, in accordance with the present invention, be used for the electrical testing of the chip, full wafer of chips or substrate or may, alternatively, be used for a more permanent connection between opposing arrays of electrical contacts.
The connector or interposer in accordance with the present invention comprises an array or matrix of closely spaced metal probes or columns held in position in a sheet of insulating material. Although various metals could be used to fabricate the probes, nickel is preferred. Typically, the insulating material would be polyimide and conventional deposition and removal techniques can be used to fabricate the array or matrix of closely spaced metal columns to form the connector or interposer in accordance with the present invention.
In accordance with the present invention, a connector or interposer is provided having an array or matrix of metal columns with each column typically being around 25 microns in diameter, 50 microns long and configured in the matrix so that they are each 50 microns on center in both the X and Y direction. Such an array may be used to test one chip at a time or a full wafer of chips at the same time with an AC bandwidth in excess of 1 GHz.
Accordingly, it is an object of the present invention to provide an electrical connector or interposer which makes good electrical contact between highly dense opposing sets or arrays of electrical contact points.
It is another object of the present invention to provide an electrical connector or interposer which does not require alignment to make good electrical contact between opposing arrays of electrical contact points.
It is a further object of the present invention to provide an electrical connector or interposer which may be used to test a single chip or a full wafer of chips.
It is yet another object of the present invention to provide an electrical connector or interposer which may be used to test a single chip or a full wafer of chips having clock speeds up to 1 GHz.
It is yet a further object of the present invention to provide an electrical connector or interposer which makes good electrical contact to each of a highly dense array of contact points for either temporary or permanent connection.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings wherein like reference numbers represent like parts of the invention.